$ make PLATFORM=cygwin "PREFIX=C:/chicken/"
gcc -fno-strict-aliasing -fwrapv -DHAVE_CHICKEN_CONFIG_H -DC_ENABLE_PTABLES -c -Os -fomit-frame-pointer  -DC_BUILDING_LIBCHICKEN library.c -o library-static.o -I. -I./
In file included from library.c:9:
chicken.h:166:11: fatal error: alloca.h: No such file or directory
  166 | # include <alloca.h>
      |           ^~~~~~~~~~
compilation terminated.
make: *** [rules.make:121: library-static.o] Error 1